Fighter VTOL 4+1 fixed wing

Hi Duane

Thanks for your great information and links to follow up with my Common Ground question.

It is something that needs to be right otherwise yes there will potentially be $$ going up in smoke…

I checked out the freeman after your suggestion, but didn’t end up going down that route - instead just ordered a MFE Striver as my first Quadplane build - and rather than trying to covert my believer - set that up as a belly lander…I like the 4+1 configuration and at 7Kg the Striver should be ideal for my 6S setup…I will probably order a Fighter as well…and would set that up as a 12S to take advantage of all that it offers.

Thanks again.

Cheers

Jeff

Hi Christian,

Thanks again for your great information with regards to the common ground question.

I have some good suggestions too from Duane and should seek Rolf’s advice as well…yes Magic Smoke can be expensive and very alarming to watch! I have fried some LED’s by over voltage, in the past but thankfully no expensive components - Yet! I always use a Smoke Stopper when I first plug in so hopefully that will at least catch some problems…

Thanks for the info on the connectors - I have XT-60’s and Deans etc on most of my Lipo’s so I was going to replace these all with XT-90 so I have consistent connections and so I don’t need to use adaptors on these…soldering downstream is a good idea to reduce points of failure and weight…it all adds up! anti-spark connectors would be good too.

Thanks again

Cheers

Jeff

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Jeff, no worries. I’m happy to try and help save the head banging on the desk/wall of others if possible. I’ve been down many rabbit holes on this adventure.

Consistent connector size makes the charging easy.

I am using the stock connector size on the batteries since my battery circuits are in series (double voltage, same capacity, same current). If I were to connect in parallel then I’d consider upgrading the connections to handle the increase in current (i.e., if expecting constant flow at 60 Amps then I’d upgrade to XT90).

Just be sure to not cross the battery cables when removing and adding a new connector- it’s a quick lesson that you only need once! ha

Cheers,
Christian

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If it was the EMLID M2 kit, it comes with a helical antenna and doesn’t require a ground plane. In the video, it appears to be mounted at the rear GPS spot by the tail which is where I have mounted mine. Fits nicely there.

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Hi Christian

Yes that is a nicer solution than the Tallysman antenna…

Cheers

Jeff

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Share an introduction and video of Striver mini VTOL.
Striver mini VTOL

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Hi Christian, I ordered an EMLID helical antenna - thanks for the inspiration - it definitely will be a nicer installation and no ground plane required! It still works with the M+ but only L1 and it is in then in place for when I upgrade to M2.

It will be nice to see some more photos of your overall component installation.

I have switched camps for now and will build a Striver first, as I figured that as a 6S system, I can build it out nicely to almost MTOW capacity - and then when I re-visit my Fighter build, I can do so without interrupting my working machine - and I will come back to the mixed battery idea, but all as 12S.

Actually as I mentioned earlier - I will probably also build a hack VTOL platform using a Volantex Ranger EX - massive fuse but probably not much in the way of payload capacity - but a good test bed for VTOL ideas…3D printed camera mounts and 1/2 axis gimbals etc…it doesn’t need to be built for endurance - just proof of concept and if it crashes - well, so be it… I might just use a cheaper FC than the Orange Cube though…

Cheers

Jeff

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Hi Jeff

I use the helical antenna that came with the M2 and I do use a ground plane it states that its optional but it made a big difference

I did try it and it was a bit disappointing I think I had a fixed lock on about 3 occasions I tried for about 3 months to get it to work reliably but gave up in the end

The RX1R Mk II needs 3.7v so 1s I have 1S 3P the batteries are 3200Mah

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Hi Christian

The Herelink is an excellent piece of kit it has never dropped out and the video transmission has been faultless although we have only tested it out to 500m

I used the default Plane parameters the tuning was quite easy

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Hi Jed,

Thanks for your responses.

That’s very disappointing about the Here+ RTK but I guess if the EMLID system serves as the primary and reliable RTK component in the system, then it doesn’t matter. I have the M+ still in its box, but don’t know if I will bother with it at all, given your experience with it.

How big did you need to make the ground plane to make the helical antenna work properly for you? How did you end up mounting this assembly on the aircraft - you mentioned in your post that it required some work to get it optimised… any photos that you don’t mind sharing? I have been using plain copper clad fibreglass PCB sheet that I use for my tallysman antenna - do you use something like that for your groundplane?

With regards to the physical connection between the M2 and the Pixhawk, do you use the M2’s S1 port plugged into the Pixhawk 2.1 (CUBE) carrier board via the 6 pin cable to GPS 2 port to receive the RTK corrections through the system with the RFD radio plugged into the telemetry port of the Pixhawk - or do you need to have a feed directly from the RFD radio to the M2? Some more detailed information on this setup would be most appreciated.

Cheers

Jeff

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Hi Christian

Well I only switched to the Striver idea temporarily - Changed my mind and changed the order - I now have a Fighter on the way…The Striver seemed like a good idea (and looks like a great airframe) but I was going to run out of space and would have been at MTOW very easily…So the fighter it is, as it will allow more options for payload…I have a whole lot of bits and pieces for a conversion too - and I think I might turn my attention to my believer and see if I can keep it setup as a twin tractor and add VTOL…options…options…Ranger Ex will still get the VTOL treatment…

I bought a T-motor AT4120 KV500 and have an 80amp ESC - so obviously a 6S setup but I thought I will still set the fighter up 6S for the cruise with two 12500 mAh Li-Ion batteries in parallel for 25000 mAh capacity and a 12S VTOL System maybe with two 4000mAh Lipo’s in series. This 12500 Foxtech Li-Ion idea comes from reading one of your earlier posts but I am doubling it up parallel 6S and more flight time potential. I am very interested in hearing about your spilt battery system performance once you get operational.

Cheers

Jeff

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@Jed_Freeman

I can give you a report on range once I get the Herelink buttons working for the VTOL modes.

Did you have any issues getting Q_* modes to activate using the Herelink remote? Do you mind sharing your parameter file? At a minimum I’d like to compare values for the FLTMODE_* to see if that is what the problem is.

Cheers,
Christian

Thanks Greg,

I just plugged in your Fighter PNG to my Horus model screen - looks great…thanks.

Cheers

Jeff

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Since I’m grounded for a bit due to software issues, I decided to take a few new photos of my VTOL build to share with others. I’ll add brief details among the photos for some aspects of the build that may have deviated from my initial plans.

Approximate weights (± 30 g using a hanging fishing scale) are as follows:
Dry 6.53 kg
Wet 10.33 kg (without multispectral camera)
MTOW 10.78 kg


Photo 1. Airframe pieces.


Photo 2. Airframe assembled.


Photo 3. Airspeed sensor Pitot tube.


Photo 4. Airspeed digital sensor board mounting.

I decided to nix the idea of using a PDB in the wings and just solder the power connections for the VTOL motors so I could save some weight.


Photo 5. VTOL power circuit wire junction inside wing.

The Mauch Power Cube has the option to use an external switch to control power to the board. This made things very convenient as I was testing different connections since I didn’t have to plug/unplug the Primary batteries each time I cycled power. The LED will be solid when the board is powered and blink intermittently when powered off but still has the batteries connected. I highly recommend considering the power switch if you use a Mauch Power Cube.


Photo 6. Switch for Primary system power board (Mauch power switch).

The soldering and routing of wires for the VTOL motors and ESC’s were a little tricky to sort out at first. After I had decided how I’d approach the problem everything went fine. On the first motor I soldered bullet connectors so that I could test spin direction on the bench. Afterwards, I resoldered the wires directly for the first and each subsequent CW and CCW motor accordingly. I had to cut out a little bit of foam in the Fighter shipping box so that there was space for the externally mounted ESC’s. I still stand by my earlier recommendation of going with the TMotor integrated arms to save you time and hassle during the assembly phase.


Photo 7. VTOL motor and ESC final external mounting.

The RC antennas used are made by Airbot and meant for the Herelink system. Their advantage over the stock Herelink antennas is that these are easily removable. They are mounted nearly perpendicular w.r.t. each other for signal coverage because they are omni-directional antennas. I went back and forth on whether to mount the FPV camera now or wait until later since it wasn’t an immediate necessity. I went for it and I decided to make a polycarbonate mount for the camera which was very simple to implement (vs. firing up the 3D printer). I used cold breaking/forming (bending) techniques and only had to attempt it once to get the right fit. This mount allows for adjustment to the camera pitch. Later I would like to remount with a servo so I can pan inflight…


Photo 8. FPV camera mount and radio antenna mounts.

The FPV system consists of the camera board and the analog-to-digital video converter. The converter is quite bulky in its case and after removing the plug connectors to save weight (thanks for the tip @GregCovey) the board is still wide but pretty thin. Everything fits nicely inside the recess in the front hatch cover. The camera board and converter get hot without air flow so I added a polycarbonate cover for protection and a 5V muffin fan. The fan pushes cabin air toward the hot boards and exhausts either through the holes in the polycarbonate or outside the airframe through the hatch penetration. This has worked great managing heat thus far with the Fighter sitting on the ground, hatches closed. I used some of the leftover MFE plastic anchor inserts to attach the cover.


Photo 9. FPV camera system in front hatch.


Photo 10. Front hatch internals.

Each power circuit (Primary, VTOL) uses a PDB as the main junction. I didn’t have the right epoxy/resin to “pot” the exposed contacts so I opted to sandwich the PDB’s between two pieces of polycarbonate. This provides protection, an attachment surface, creates an air gap between the foam frame and the exposed solder joints, and allows access to the PDB’s for future power modifications.


Photo 11. PDB for the Primary power system circuit.


Photo 12. Front hatch internals with Primary circuit batteries installed.

The Herelink Air unit gets hot without active air flow, even in open spaces.The unit fits well inside the RC hatch, however, it requires airflow so a 5V muffin fan was recessed into the hatch to be minimally invasive inside the compartment. The fan pulls in outside air for cooling.


Photo 13. Herelink Air RC unit mounting location.


Photo 14. Cargo hatch GPS mounting position.


Photo 15. Cargo hatch internals.

To support the weight of the VTOL system batteries I made a polycarbonate battery tray reinforced with carbon fiber spars laterally and then carbon fiber uprights. This helps to transfer the load to the central wing spars so the extra weight is not being held solely by the foam sides and bottom of the fuselage. The battery tray is removable as well as the rear carbon fiber uprights (note: rearward central wing spar is removable via a clever MFE design). Because the battery tray is removable it allows for a slung payload sensor (or another payload arrangement) in my next building phase.


Photo 16. Cargo hatch internals, battery tray and multispectral sensor mount.


Photo 17. Cargo hatch internals with VTOL circuit batteries installed.


Photo 18. Cargo hatch internals with multispectral camera mounted


Photo 19. Multispectral camera mount in belly of plane (rough fit)

Mounting the multispectral camera against the belly of the fuselage made it protrude further than I was comfortable with. I added a 1.5 cm thick, medium-density foam to help recess the camera and provide a secure, padded, compressive mount for the camera.


Photo 20. Multispectral camera mount in belly of plane with battery tray and foam padding offset.

Herelink ground unit/controller fits nicely in a small Pelican case.


Photo 21. Herelink Ground unit in transport case.

Bit of a firehose type of post, I partly apologize, but I’ve been busy in many things and haven’t been able to update progress!

Cheers,
Christian

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Looking very good Christian.

Cheers

Jeff

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Hi Christian,

Thanks for posting the photos. It looks like a pro build!

I like the way you utilized the underside of the hatches. You have more “stuff” inside your Fighter but it still fit well.

How did you end up securing the receiver hatch? I had to access mine a few times and got tired with removing the four screws so I ended up taping it with white duct tape. I would have preferred it if MFE used a latch design on all the hatches.

Cheers!

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Thanks Greg. Somehow it all fit and miraculously doesn’t look like a complete Mickey Mouse job. :slightly_smiling_face:

I just used the default MFE method with screws. Fortunately, I don’t need regular access to this compartment.

Still need to hookup the ViFly Finder unit and apply the covering film on the foam once electronics are GTG if no further body modifications are required.

Cheers,
Christian

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Wow! What a fantastic update! Thank you for sharing so many photos with us.

I’m very curious about the multispectral camera. Did I miss a post where you provided details about the camera? If not, I’m hoping you’ll share some of the details.

I have a “RTF” version of the Freeman on the way. (I think “RTF” just means it includes motors ESCs and and servos.) I will likely try putting together the Freeman kit which includes all motors and ESCs before I do much more work on my Fighter.

Thanks again for the great update.

Edit: After a bit of research, I think the camera is this (or similar):

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No worries! It’s not like it is some trade secret and I know that pictures help more than text alone for most. Happy to contribute to the community and help others with their builds since I have gained a lot of knowledge here.

Yes, it is the Micasense Altum multispectral camera in my Fighter build. My previous build used a Micasense Rededge MX which is much smaller and lighter. One thing to be aware of is that the Altum thermal band goes through a recalibration every 5 minutes or 2 degrees C change (https://support.micasense.com/hc/en-us/articles/360036377834-Altum-Thermal-Band-FAQ). The recalibration takes approx. 3 seconds which isn’t terrible unless it’s in the middle of a flight line resulting in a data gap in all bands captured.

Currently I am working on the MAVLink communications (bit of a learning curve) to command when the recalibrations occur. Ideally, I would like to have recalibration take place when the VTOL is making a turn between its flight lines. I haven’t tested if turning off the thermal band during image capture disables recalibrations completely. Either way, I will need to control the process for missions.

Cheers,
Christian

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Hi Greg,

Just wondering, in your experience with the FrSky (primary and satellite) receiver pair that you use in your Fighter, in conjunction with your Horus X10S, what would be the maximum range that you would expect to see to maintain a reliable RSSI connection and retain the primary Tx control of your aircraft? Have you ever tested these limits to invoke a (real) loss of Tx failsafe in a flight?

I am thinking FrSky X8R and XM+ combo (I have spares in hand already)…or do you have any other recommendations on FrSky long range receivers (with telemetry)? My Horus is X10S Express so has ACCST and ACCESS.

I know that there are many variables at play here, but just trying to get an idea of what to expect with regards to a realistic and reliable maximum range of this receiver combo, versus using the theoretical (peace of mind) 40Km Tx and telemetry control range (not that I will be using that range anyway) of the RF Designs TX MOD in the Horus external module bay.

If I used these receivers for primary Tx (and the FrSky telemetry back to the Horus), I would still have the backup of a pair of RFD900x in the standard configuration for coms round tripping via Mission Planner…

My other option is to use the TXMOD in the Horus’ module bay and provide Tx through 16 channels of PPM from this and output from the airside RFD900x to the Pixhhawk RCIn so I have all in one control and telemetry/coms to/from mission planner (wifi to PC from TXMOD) etc and get the benefits of the extended range…however, then there is the potential downside risk of having both systems operating from the one Tx unit…ie in the unlikely event to lose the Tx power for example - both systems are down. Fall-back to failsafe but no coms at all…

Further to this, would it be possible to use the RFD TXMOD as the primary Tx control and coms to Mission Planner and then SBUS/Sport back out to X8R to enable the FrSky telemetry to the Horus as well - assuming that is still within RSSI range?

Anyone else reading this post - please feel free to add your thoughts. and experiences

My Fighter arrived - China to Australia in about two weeks…which is quite a reasonable time frame in our current worldwide logistics climate - quite a hole pierced through the bottom of the cardboard carton but thankfully no broken aircraft parts - just some small repairs to restore the polystyrene carrier…and only a few small compressions and scratches to the airframe parts - so overall a successful journey…I have read of others having various problems with big delays and various levels of damage (it is always a bit of a gamble and I have had my share of problems with other deliveries) however I thought I should share this positive experience.

Cheers

Jeff

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